US4750069A - Head mounting in magnetic storage devices - Google Patents
Head mounting in magnetic storage devices Download PDFInfo
- Publication number
- US4750069A US4750069A US06/864,164 US86416486A US4750069A US 4750069 A US4750069 A US 4750069A US 86416486 A US86416486 A US 86416486A US 4750069 A US4750069 A US 4750069A
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- US
- United States
- Prior art keywords
- head
- magnetic
- fixture
- magnetic tape
- tape head
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
- G11B5/4806—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed specially adapted for disk drive assemblies, e.g. assembly prior to operation, hard or flexible disk drives
- G11B5/4826—Mounting, aligning or attachment of the transducer head relative to the arm assembly, e.g. slider holding members, gimbals, adhesive
Definitions
- This invention relates to magnetic storage devices. More particularly, this invention relates to techniques for mounting and securing magnetic heads (e.g., read/write heads) in such devices. Even more particularly, this invention relates to techniques for obtaining proper alignment of magnetic heads in such devices at the time of mounting.
- magnetic heads e.g., read/write heads
- a head in a magnetic storage device e.g., tape drive apparatus or hard disk apparatus
- a magnetic storage device e.g., tape drive apparatus or hard disk apparatus
- the tape must be in intimate contact with the head and accurately aligned to it.
- the head In a magnetic disk storage device, the head must also be properly aligned and mounted relative to the magnetic disk.
- the most important alignment parameters which must be controlled are those which influence azimuth angle, tape flying height (distance between the tape and the head), and off-track error.
- the azimuth angle head-gap to tape-path angle
- the tape flying height is a function of tape tension, tape wrap angle, head penetration, yaw, zenith and head geometry.
- Off-track error head gap position relative to the written track
- can introduce erroneous data sensing e.g., from adjacent tracks).
- Some of these parameters may be controlled by factors such as head design, head actuation system, and cartridge referencing (e.g., in a tape drive apparatus).
- head design head design
- head actuation system head actuation system
- cartridge referencing e.g., in a tape drive apparatus
- the position of the head is determined by three linear dimensions (penetration, offset, and off-track) and by three angular dimensions (azimuth, yaw, and zenith). The accuracy of placement of the head in each of these dimensions controls the performance of the head.
- One manner of aligning and mounting a magnetic head in a magnetic storage device is to temporarily fasten the head to a carrier or support in the device itself and then align the head to the desired position optically.
- Such technique requires the use of a microscope (at least 500 ⁇ to 1000 ⁇ ) in order to see the head gap (i.e., the gap between the two halves of the magnetic core for a read head, write head, or a read/write head).
- Special tooling is required to support the apparatus in a designated plane. Then, using the microscope, it is necessary to visually align the head gap to a position which is believed to be perpendicular to the designated plane.
- Another manner of aligning a magnetic head in a magnetic storage device involves initially pre-mounting the head in a manner such that it can be moved slightly in order to align the azimuth prior to permanent mounting. Then the head is magnetically aligned using a specially prepared magnetic media (e.g., a tape, floppy disk, etc.) which has the flux transitions recorded at predetermined azimuth errors in a manner such that the amplitude of the signals read by an azimuth aligned head correspond with a predetermined pattern.
- a specially prepared magnetic media e.g., a tape, floppy disk, etc.
- One disadvantage of this technique is that it requires use of a specially prepared magnetic media which is expensive. Also, some of the allowable tolerance is already lost due to errors in the recording of the media itself. Furthermore, each head must be individually aligned. This technique also requires micro-manipulation or adjustment of the head during alignment.
- Another manner of aligning and mounting a magnetic head (of the type having at least a pair of gaps on the same gap plane) in a magnetic storage device such as a tape drive apparatus involves the use of a precision fixture which simulates a tape cartridge or cassette. The head is aligned and clamped to the fixture. Then the fixture is inserted into the tape drive apparatus which clamps and references the fixture to the drive mechanism. This procedure fixes five of the degrees of freedom (all but the azimuth). The head is then tacked with adhesive to a bracket, which in turn is held to the tape drive by a small removable clamp. The preliminary fixture simulating a tape cartridge is then removed and the head is ready for azimuth adjustment. The small removable clamp holds the head and bracket assembly against the head carrier but it allows rotation of the head so as to enable adjustment of the azimuth angle.
- Yet another technique for aligning a magnetic head involves a reference surface transfer.
- this technique it is necessary to grind an external surface of the magnetic head to form a surface which is either perpendicular to the gap surface or parallel to the gap surface.
- the surface which has been so ground is then used as a reference surface to determine alignment of the head.
- One disadvantage of this technique is that the magnetic head becomes more costly because of the precision grinding required. Also, some tolerance is lost due to the grinding process.
- This technique may be used as the preliminary mounting procedure when using any of the other foregoing techniques when tight tolerance is required.
- novel techniques for aligning and mounting a magnetic head in a magnetic storage device e.g., tape drive apparatus or magnetic disk apparatus.
- fixtures which facilitate the alignment and mounting of a magnetic head to a support carriage in the magnetic storage device.
- a magnetic head is configured such that access may be gained to the plane which defines the interface between the two halves of a magnetic core in the head. Then the head is mounted on a fixture which causes the plane or interface to be properly aligned before the head is permanently secured to a support carriage in the magnetic storage device. Thus, the head is very accurately aligned in a one step procedure which is very rapid. This reduces assembly time and minimizes or eliminates opportunities for human error or instrument error in obtaining proper alignment. No measurements need be taken during assembly to determine proper alignment of the head.
- the techniques of the present invention also avoid the error inherent in the use of an external reference surface. Use of the techniques of the present invention results in considerably total cost savings for a mounted magnetic head.
- FIG. 2 is a front view of the portion of the fixture of FIG. 1 which is adapted to hold and align a magnetic head during the mounting procedure;
- FIG. 3 is a top view of the fixture shown in FIG. 1 prior to insertion of the magnetic head;
- FIG. 7 is a front view of the magnetic head shown in FIG. 6;
- FIG. 7A is an explosion view illustrating the separate components of the magnetic head shown in FIGS. 6 and 7;
- FIG. 8 is a front view, enlarged, of a portion of the magnetic head illustrated in FIGS. 6 and 7;
- FIG. 10 is a perspective view illustrating yet another embodiment of magnetic head design of this invention.
- FIG. 13 is a top view illustrating the magnetic head precursor of FIG. 11 after additional processing steps
- FIG. 14 is an end view of the magnetic head precursor shown in FIG. 13;
- FIG. 15 is a top view of several magnetic heads (i.e., sliders) produced from the precursor shown in FIG. 13;
- FIG. 16 is a side view of one of the magnetic heads shown in FIG. 15;
- FIG. 18 is a perspective view illustrating an embodiment of a fixture which is an integral part of a magnetic storage device in accordance with the techniques of the present invention.
- FIGS. 1, 2 and 3 there is shown a fixture 10 which simulates a tape cartridge or tape cassette which is adapted to be inserted into a conventional tape drive apparatus.
- the fixture includes a base portion which is identical to a particular tape cartridge base of the type which is compatible with the particular tape drive apparatus in which a magnetic head is to be mounted.
- the tape drive apparatus accurately locates and holds the fixture when it is inserted into the tape drive apparatus. Therefore, the magnetic head (when held in the fixture) will be properly located and oriented relative to where the tape media travels when the fixture is placed into the tape drive apparatus.
- FIG. 4 there is illustrated fixture 10, having magnetic head 25 temporarily supported thereon, and there is also shown conventional tape drive apparatus 30.
- Fixture 10 since it simulates a tape cartridge or tape cassette compatible with the tape drive apparatus, may be slidingly engaged within tape drive apparatus 30 in the same manner as a tape cartridge would be inserted therein.
- mounting bracket 27 After fixture 10 has been fully inserted into tape drive apparatus 30, mounting bracket 27 will abut against the front edge 32 of head carrier support 31 in tape drive 30.
- Head support carrier 31 is mounted within frame members 33 and 34 in a manner such that the carrier may be made to move vertically during the normal operation of the completed tape drive apparatus to access various tracks on magnetic tape in a tape cartridge.
- FIG. 5 illustrates one manner in which the mounting bracket 27 may be held firmly in place against front edge 32 of head carrier 31 during the mounting process.
- Spring clip 35 is adapted to be slidingly received onto the front portion of head carrier 31 and is also adapted (via finger 36) to temporarily secure mounting bracket 27 flat against front edge 32 of carrier 31.
- the magnetic head 25 is still supported in proper alignment attitude by means of fixture 10 (not shown in this figure).
- a small amount of adhesive may be placed along the abutting surfaces of bracket 27 and front edge 32 of carrier 31 so as to spot tack bracket 27 to the carrier 31.
- a small amount of adhesive is also applied to abutting edges of magnetic head 25 and bracket 27 so as to spot tack the head 25 to bracket 27.
- the magnetic head 25 is fixed in position relative to bracket 27, and bracket 27 is fixed in position relative to head carrier 31.
- a more permanent bonding adhesive is applied to all abutting surfaces of magnetic head 25 and bracket 27 to permanently secure the head to the bracket.
- Permanent adhesive is also applied at this time to all abutting surfaces of bracket 27 and front edge 32 of head carrier 31. After the adhesive has cured the magnetic head is thereby permanently and fixedly secured to the head carrier 31 in proper alignment attitude as required for proper use in the tape drive apparatus 30.
- the fixture illustrated in FIGS. 1-4 simulates a tape cartridge or tape cassette and is capable of temporarily holding and positioning a magnetic tape head while anchoring it to the support carrier or support carriage during the manufacture and assembly of tape drive apparatus.
- the fixture is adapted to hold the magnetic head in the very precise alignment attitude which is required in order to properly and permanently anchor or mount the magnetic head to the tape drive apparatus.
- FIGS. 6, 7, 7A and 8 illustrate in more detail one embodiment of a preferred magnetic head design of this invention.
- this embodiment there is a groove or recess 26 along the top edge of the magnetic head, and there is a similar groove or recess 24 along the bottom surface of the magnetic head.
- the grooves or recesses 24 and 26 are placed in a manner such that one edge of each groove or recess corresponds with the plane defining the interface between the I-block and the C-block of the magnetic head.
- One-half of the magnetic core of the magnetic head is contained within the I-block and the other half of the magnetic core is contained within the C-block.
- the head gap between the two halves of the magnetic core is within the interface between the I-block and the C-block.
- FIG. 7A This is illustrated in more detail in the explosion view of FIG. 7A in which the I-block 25a is sandwiched between two C-blocks 25b and 25c, as shown.
- the I-block 25a and C-block 25c each form one-half of a magnetic core
- I-block 25a and C-block 25b each form one-half of another magnetic core.
- Groove or recess 26 along the top edge of C-block 25b, and groove 24 along the bottom edge of C-block 25b, are formed or cut prior to assembly of head 25.
- the grooves 24 and 26 are disposed in a manner such that one edge or wall of each such groove corresponds with the interface between the two halves of the magnetic core, as described above.
- a fixture such as shown in FIGS. 1, 2 and 3
- the edge of each groove or recess which corresponds with the interface between the two halves of the magnetic core is positioned against a tab or rail whose position corresponds exactly with what is required for proper alignment of a magnetic head for a particular tape drive apparatus.
- FIG. 9 there is illustrated another embodiment of magnetic head 40 of this invention which also contains means for accessing the interface between the I-block and the C-block.
- this embodiment there are provided a plurality of apertures 42, 43 and 44 extending through the C-block.
- the apertures extend inwardly to the surface of the I-block which defines the interface between the two halves of the magnetic core. Accordingly, this embodiment of magnetic head may be properly aligned by means of a fixture which includes pins, for example, which are adapted to be slidingly received by apertures 42, 43 and 44.
- the apertures may instead be provided through the I-block to the surface of the C-block.
- the cross-sectional shape of the shaft may be complementary to the shape of the aperture, or the shaft may fit within the aperture along with something else (e.g., a key, or a spring). It is also possible for the shaft to comprise more than one piece. A portion of the shaft contacts the interface between the two halves of the magnetic core.
- the term magnetic head refers to and includes any head which includes two halves of a magnetic core positioned in the head so as to form a gap.
- the magnetic head may include one or several of such gaps.
- the magnetic head may function as a read head, a write head, or as both. Indeed, a single magnetic head may include more than one read or write gap. Also, a single magnetic head may include more than one gap surface (e.g., as illustrated in FIGS. 6, 7 and 7A).
- magnetic head as used herein also includes what is known in the art as a thin film head where the magnetic layers are built up on a lapped surface using thin film deposition processes.
- the interface between the two halves of the magnetic core in various other manners.
- a fixture which includes tabs or rails or protrusions to physically contact the interface
- light beams e.g., laser beams
- one or more laser beams may be directed at the interface (e.g., through apertures, grooves, slots, etc.) in order to determine the exact alignment of the magnetic head. This may be done using a three point distance technique or an auto-columnation technique.
- FIGS. 11-17 there is illustrated a process for forming another type of magnetic head in accordance with the principles of the present invention.
- FIG. 11 there is shown a top view of portions of two magnetic ceramic materials 60 and 62. These two materials eventually form the two halves of a magnetic core.
- Material 60 includes one edge 61 which is a lapped surface.
- Material 62 includes raised portions 63, separated by channels 65. The top surface of each raised portion 63 is also a lapped surface.
- a side view of these materials 60 and 62 is shown in FIG. 12.
- Material 60 forms the I-block, and material 62 forms the C-block of the magnetic core.
- Cavity 66 separates raised portions 63 and 64. The gap is formed between raised portion 63 and lapped edge 61. Contact between raised portion 64 and lapped edge 61 forms the flux return path.
- FIG. 13 there is shown a top view of the magnetic head precursor in which lapped surface 61 of material 60 has been bonded to the top surface of raised portion 63 of material 62 (e.g., they have been bonded together by means of a conventional glass bonding technique well known in the art). Then channels 67 and 68 have been ground into the top surface of the structure so as to leave ridges 70 spaced therealong (as illustrated in FIGS. 13 and 14).
- FIG. 14 is an end view of the precursor shown in FIG. 13.
- the precursor structure of FIG. 13 is then sliced or cut into individual sliders (i.e., mini-monolithic magnetic heads) as illustrated in FIG. 15. Subsequent to that operation portions of material 62a are removed so as to leave exposed areas of surface 61 (which is the interface between the two halves of the magnetic core).
- FIG. 16 is a side view of one of the individual sliders shown in FIG. 15.
- FIG. 17 is an end view of one of the sliders of FIG. 15.
- FIG. 18 Another variation of the invention is illustrated in FIG. 18.
- a mounting fixture 80 which may be permanently mounted or secured to a magnetic storage device (e.g., tape drive apparatus).
- a magnetic storage device e.g., tape drive apparatus
- fixture 80 may be made of plastic, and it may be molded or cast as an integral unit of the tape drive apparatus or as a portion thereof.
- the fixture 80 may be molded separately (e.g., of plastic) and then permanently mounted on the magnetic storage device.
- the fixture 80 includes opposing tabs 81, 82 and 83. As shown in FIG. 18, tab 81 projects downwardly from the top of fixture 80 while tabs 82 and 83 project upwardly from the bottom of the fixture.
- Tab 83 is L-shaped.
- Magnetic head 90 has a groove or recess 92 in its top surface and a groove or recess 94 in its bottom surface. Groove 92 is adapted to slidingly receive tab 81, and groove 94 is adapted to slidingly receive tabs 82 and 83 as head 90 is moved forwardly into the fixture 80. Because tab 83 is L-shaped, head 90 is prevented from sliding forwardly after the front edge of head 90 reaches portion 83a of tab 83, thus setting the penetration of the head.
- Spring 84 on fixture 80 is adapted to urge head 90 outwardly in a manner such that one side of each groove 92 and 94 is urged against the inward surface of tabs 81, 82 and 83.
- head 90 may be securely fastened to the fixture (e.g., by means of adhesive) so as to become a permanent part of the apparatus.
Landscapes
- Adjustment Of The Magnetic Head Position Track Following On Tapes (AREA)
Abstract
Description
Claims (10)
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US06/864,164 US4750069A (en) | 1986-05-16 | 1986-05-16 | Head mounting in magnetic storage devices |
US07/163,039 US4823221A (en) | 1986-05-16 | 1988-03-02 | Magnetic head with planar interface position registration means |
US07/163,339 US4811141A (en) | 1986-05-16 | 1988-03-02 | Head mounting in magnetic storage devices |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US06/864,164 US4750069A (en) | 1986-05-16 | 1986-05-16 | Head mounting in magnetic storage devices |
Related Child Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US07/163,039 Division US4823221A (en) | 1986-05-16 | 1988-03-02 | Magnetic head with planar interface position registration means |
US07/163,339 Division US4811141A (en) | 1986-05-16 | 1988-03-02 | Head mounting in magnetic storage devices |
Publications (1)
Publication Number | Publication Date |
---|---|
US4750069A true US4750069A (en) | 1988-06-07 |
Family
ID=25342665
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US06/864,164 Expired - Lifetime US4750069A (en) | 1986-05-16 | 1986-05-16 | Head mounting in magnetic storage devices |
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Country | Link |
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US (1) | US4750069A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0348559A1 (en) * | 1988-05-31 | 1990-01-03 | Hewlett-Packard Limited | Read/write heads mounting tool. |
US5311390A (en) * | 1990-06-29 | 1994-05-10 | Conner Peripherals, Inc. | Apparatus for precise positioning of a tape head and programming thereof |
US5956199A (en) * | 1995-05-26 | 1999-09-21 | International Business Machines Corporation | Head to tape alignment without tape guide |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4456938A (en) * | 1982-10-12 | 1984-06-26 | International Business Machines Corporation | Manufacturing apparatus for adjusting the position of a magnetic head in a flexible disk drive |
US4458274A (en) * | 1982-06-22 | 1984-07-03 | International Business Machines Corporation | Manufacturing method and apparatus for adjusting the position of a magnetic head in a flexible disk drive |
-
1986
- 1986-05-16 US US06/864,164 patent/US4750069A/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4458274A (en) * | 1982-06-22 | 1984-07-03 | International Business Machines Corporation | Manufacturing method and apparatus for adjusting the position of a magnetic head in a flexible disk drive |
US4456938A (en) * | 1982-10-12 | 1984-06-26 | International Business Machines Corporation | Manufacturing apparatus for adjusting the position of a magnetic head in a flexible disk drive |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0348559A1 (en) * | 1988-05-31 | 1990-01-03 | Hewlett-Packard Limited | Read/write heads mounting tool. |
US5311390A (en) * | 1990-06-29 | 1994-05-10 | Conner Peripherals, Inc. | Apparatus for precise positioning of a tape head and programming thereof |
US5956199A (en) * | 1995-05-26 | 1999-09-21 | International Business Machines Corporation | Head to tape alignment without tape guide |
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AS | Assignment |
Owner name: HEWLETT-PACKARD COMPANY, PALO, ALTO, CALIFORNIA A Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:MC CONICA, CHARLES H.;MIKSCH, EUGENE A.;WANGER, MARK E.;REEL/FRAME:004848/0091 Effective date: 19860516 Owner name: HEWLETT-PACKARD COMPANY,CALIFORNIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:MC CONICA, CHARLES H.;MIKSCH, EUGENE A.;WANGER, MARK E.;REEL/FRAME:004848/0091 Effective date: 19860516 |
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Owner name: HEWLETT-PACKARD COMPANY, COLORADO Free format text: MERGER;ASSIGNOR:HEWLETT-PACKARD COMPANY;REEL/FRAME:011523/0469 Effective date: 19980520 |